铁基粉末冶金件的化学表面改性处理

The Chemical Surface Modifying Heat Treatment of Iron-base Powder Metallurgical Parts

化学表面改性处理的铁基粉末冶金件表面可获得比普通热处理更高的硬度、耐磨性和疲劳强度,同时心部保持良好的塑性和韧性。应尽量选择高密度粉末冶金材料。化学表面改性处理通常在气体介质炉中进行,温度、保温时间及气氛的控制很关键。一般首选渗碳处理。淬火和回火和影响零件的最终品质,在铁基粉末冶金材料中加入合金元素可提高其淬透性。可采用蒸汽处理、渗硫和碳氮共渗等不同方法来满足各种零件不同的使用功能。

The iron-base powder metallurgical parts after surface modified chemically can obtain much higher hardness,wearing capacity and fatigue strength than those heat treated conventionally,and the heart part maintains well plastic and ductile.The chemical surface modifying heat treatment is usually undertaken in a gas medium furnace with the temperature,soaking time and atmosphere control being as key points. Generally carburization is first selected.Both quenching and tempering affect the final qualities of the parts. The hardenability can be improved if alloy elements are added to the iron-base powder metallurgical ma-terial.Steam treatment,sulfurizing and carbonitriding can be used to meet the various service functions.